If you’ve ever stood in front of a complete fossil of a Tyrannosaurus rex, there’s no doubt that it was the apex predator of its era. The adults had huge skulls and rusty teeth the size of bananas. A fully developed D. The strength of the rex’s bite has been the subject of many scientific studies, but mysteries persist about what led to this powerful anemone that ruled the end of the dinosaur era.
In Research Published in the September issue of The Anatomical Record, T. A team of scientists tried to understand the oral weapons of the tyrannosaur species that roamed the Asian and North American landscapes for millions of years before the rex. By measuring bite forces and tyrannical cranial stress, the researchers showed that tyrannosaurs steadily developed their bone-crushing powers over the ages. D. They also found that rex can deliver a really nasty bite, even at its young age.
Creating 3-D skull models of the nine tyrannosaur species for their analysis was not easy for the researchers. University of Chicago doctoral student Evan Johnson-Ransom, who led the research, said reconstructing the digital skulls of the two Asian species “took about three months of working with flat specimens.”
But the team persevered and eventually found that tyrannosaur noses fit two basic patterns: the earlier forms of tyrannosaurs and juvenile T. Kinder for lean ones like Rex, then stronger for big noses like Big T. Rex then subjected each 3-D model to finite element analysis, a technique for determining stress and strain in biological structures. Stress, in this context, refers to the amount of force exerted on the bones of the skull that are capable of handling intense exertion.
Under moderate-to-high-stress conditions, the skulls “do a lot of biting or more strenuous work while feeding,” Mr. Johnson-Ransom said. Low stress indicates that one tyrannosaur species did not bite as hard as others.
Some of the results were expected: the larger the tyrannosaur species, the greater the bite force.
Other results were more surprising: the shape of a nose does not necessarily correlate with the pressure of the skull. In fact, some earlier, gracile-snouted tyrannosaurs had low skulls, which meant “they didn’t bite as hard,” Mr. Johnson-Ransom said. But when an animal like T. rex crushed its prey with its bite, the pressure on its skull was too much.
Emily Rayfield, a paleobiology professor at the University of Bristol in England who was not involved in the study, praised the researchers for overcoming past technical limitations with their analysis. But the T. rex results surprised her.
“Their broad skulls are packed with more jaw-closing muscle, which means they can bite disproportionately harder, but their skulls are comparatively more compressed.”
Before reaching maturity in adulthood, juvenile D. Rex had a fine nose. The new research highlights that a young T. rex’s feeding skills, when it tackles larger prey with its skull and bite, occupy a different ecological niche from the environment it grew up in as an adult.
But even as a teenager, D. The study shows that rex had jaw-muscle power that produced a stronger bite than non-rex tyrannosaur ancestors. It is a powerful predator regardless of age.
Other researchers said the discovery could be one of the most valuable parts of the study.
“Adult Tyrannosaurus didn’t exist in a vacuum,” said Thomas Holtz, a vertebrate paleontologist at the University of Maryland who was not involved in the research. “Every adult T. rex must first live as an infant and juvenile, and Tyrannosaurus is the product of a long evolutionary history.”
The authors hope their methods can be applied to other, less studied dinosaurs. Mr. Johnson-Ransom has already begun, showing what finite element analysis can tell about spinosaurs at a Society of Vertebrate Paleontologists meeting in October.
